.TH std::array::data 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::array::data \- std::array::data

.SH Synopsis
   T* data() noexcept;             \fB(1)\fP \fI(since C++11)\fP
                                       (constexpr since C++17)
   const T* data() const noexcept; \fB(2)\fP \fI(since C++11)\fP
                                       (constexpr since C++14)

   Returns pointer to the underlying array serving as element storage. The pointer is
   such that range [data(), data() + size()) is always a valid range, even if the
   container is empty (data() is not dereferenceable in that case).

.SH Parameters

   \fI(none)\fP

.SH Return value

   Pointer to the underlying element storage. For non-empty containers, the returned
   pointer compares equal to the address of the first element.

.SH Complexity

   Constant.

.SH Notes

   If size() is 0, data() may or may not return a null pointer.

.SH Example


// Run this code

 #include <cstddef>
 #include <iostream>
 #include <span>
 #include <array>

 void pointer_func(const int* p, std::size_t size)
 {
     std::cout << "data = ";
     for (std::size_t i = 0; i < size; ++i)
         std::cout << p[i] << ' ';
     std::cout << '\\n';
 }

 void span_func(std::span<const int> data) // since C++20
 {
     std::cout << "data = ";
     for (const int e : data)
         std::cout << e << ' ';
     std::cout << '\\n';
 }

 int main()
 {
     std::array<int, 4> container{1, 2, 3, 4};

     // Prefer container.data() over &container[0]
     pointer_func(container.data(), container.size());

     // std::span (C++20) is a safer alternative to separated pointer/size.
     span_func({container.data(), container.size()});
 }

.SH Output:

 data = 1 2 3 4
 data = 1 2 3 4

.SH See also

   front   access the first element
           \fI(public member function)\fP
   back    access the last element
           \fI(public member function)\fP
   size    returns the number of elements
           \fI(public member function)\fP
   span    a non-owning view over a contiguous sequence of objects
   (C++20) \fI(class template)\fP
   data    obtains the pointer to the underlying array
   \fI(C++17)\fP \fI(function template)\fP
